1. Technical Field
The present invention relates to a power on reset (POR) device and a POR method.
2. Description of the Related Art
Power on reset (POR) means that a digital register, or the like, is reset after a predetermined time from a point in time at which power starts to be supplied at the time of initial driving of an electronic apparatus to allow a system to be stably operated.
Further, in addition to the initial driving of the electronic device, in the case in which the supply of power becomes unstable due to various reasons, the digital register, or the like, is reset in order to protect the electronic apparatus and prevent a malfunction.
The temporal power down phenomenon as described above is called a brown out phenomenon, and an operation of detecting and coping with the brown out phenomenon is called a brown out detection (BOD).
Meanwhile, according to the related art, a circuit performing the POR and a circuit performing the BOD are generally provided, respectively. Therefore, there is a limitation in satisfying requirements such as miniaturization, slimness, and lightness of the electronic apparatus.
In addition, in the scheme of performing the BOD according to the related art, a reference voltage for detecting a brown out situation has been mainly provided in software and comparison between a power supply voltage and the reference voltage has also been mainly implemented in software. However, in the case of applying the software control scheme as described above, as the power supply voltage is unstable, it is likely that a controlling unit will malfunction, such that there is a limitation in securing stable operation reliability of the electronic apparatus.
In addition, in some case, a threshold voltage of a metal oxide semiconductor field effect transistor (MOSFET) has been used as the reference voltage for the BOD. However, since a deviation of the threshold voltage of the MOSFET according to a manufacturing process of the MOSFET or a temperature of an apparatus is large, accuracy in performing the BOD becomes low and a separate temperature compensation circuit for compensating for the low accuracy, or the like, should be included.